What can cause an abnormal EMG?
What can cause an abnormal EMG?
An abnormal EMG result may be a sign of a muscle or nerve disorder, such as:
- Polymyositis.
- Muscular dystrophy.
- Myasthenia gravis.
- Myotonic (stiff) muscles.
- Damage or disease of the motor nerve, such as can be seen with nerve disease.
What diseases show up on EMG?
An EMG can be used to diagnose a wide variety of neuromuscular diseases, motor problems, nerve injuries, or degenerative conditions, such as:
- Amyotrophic lateral sclerosis (ALS)
- Carpal tunnel syndrome.
- Cervical spondylosis.
- Guillain-Barre syndrome.
- Lambert-Eaton syndrome.
- Muscular dystrophy.
- Myasthenia gravis.
What causes abnormal nerve conduction test?

Most often, abnormal results are due to nerve damage or destruction, including: Axonopathy (damage to the long portion of the nerve cell) Conduction block (the impulse is blocked somewhere along the nerve pathway) Demyelination (damage and loss of the fatty insulation surrounding the nerve cell)
What do EMG results tell you?
Electromyography (EMG) is a diagnostic procedure to assess the health of muscles and the nerve cells that control them (motor neurons). EMG results can reveal nerve dysfunction, muscle dysfunction or problems with nerve-to-muscle signal transmission.
What does ALS look like on EMG?
The hallmark of ALS on needle EMG is chronic and active loss of LMNs innervating muscles with multiple nerve root innervation and spread within an initial body segment and to other body segments.

Can an EMG detect neuropathy?
The diagnosis of peripheral neuropathy can be supported by electrodiagnostic testing, which includes nerve conduction studies (NCS) and needle electromyography (EMG). This activity reviews some of the causes of peripheral neuropathy and the corresponding electrodiagnostic findings.
What happens if you have nerve damage?
Peripheral neuropathy, a result of damage to the nerves located outside of the brain and spinal cord (peripheral nerves), often causes weakness, numbness and pain, usually in the hands and feet. It can also affect other areas and body functions including digestion, urination and circulation.
What is the most common symptom of nerve damage?
If you have neuropathy, the most commonly described feelings are sensations of numbness, tingling (“pins and needles”), and weakness in the area of the body affected. Other sensations include sharp, lightening-like pain; or a burning, throbbing or stabbing pain.